Hybrid D.C. power controllers have been known heretofore. For example, A. Vang U.S. Pat. No. 2,789,253, dated Apr. 16, 1957, L. J. Goldberg U.S. Pat. No. 3,309,570, dated Mar. 14, 1967, W. Knauer U.S. Pat. No. 4,056,836, dated Nov. 1, 1977, M. Murano et al. U.S. Pat. No. 4,110,806, dated Aug. 29, 1978, S. Yanabu et al. U.S. Pat. No. 4,172,268, dated Oct. 23, 1979, S. Tokuyama et al. U.S. Pat. No. 4,216,513, dated Aug. 5, 1980, and K. C. Shuey et al. U.S. Pat. No. 4,249,223, dated Feb. 3, 1981, show circuits that discharge a previously charged capacitor across the contacts to provide arcless interrupters. Such capacitor discharge is controlled by an SCR or the like which is activated by sensing means that senses the arc, the voltage across the contacts, or the like.
While these prior current interrupters have been useful for opening a circuit, they do not provide means for assisting in interrupting a high voltage D.C. circuit at low atmospheric pressures of the order of 1 psi such as occur at high altitudes of the order of 80,000 feet or the like. This invention relates to improvements thereover.